Vibration absorbing device



Jan. 7, 1941. E. MARTIN 2,227,942

VIBRATION ABSORBING DEVICE Filed Nov. 2, 1938 2 Sheets-Sheetl INVENTOR.E'r/e Marfin J4 TTORNEY Jail. 7, 1941 E. MARTIN VIBRATION ABSORBINGDEVICE 2 Sheets-Sheet 2 Filed Nov. 2, 1938 Wm 9m mum/W INVENIDR. E'r/eMarzm v ATTORNEY Patented Jan. 7, 1941 I v UNITED STATES PATENT OFFICE2,227,942 VIBRATION ABSORBING DEVICE Erle Martin, West Hartford, Conn.,ass'ignor to United Aircraft Corporation, East Hartford,

Conn, a corporation of Delaware Application November 2, 1938, Serial No.238,336

6 Claims. (01. 74-604) This invention relates to improvements invierally indicated at It mounted in spaced main bration absorbingdevices and has for an object bearings l8 and 20 and operativelyconnected with the provision of an improved vibration absorbing thedrive shaft I2 either directly or through some arrangement for a powerplant such as an internal suitable form of reduction gear mounted in thecombustion engine. nosepiece [4. The crankshaft l6, as illustrated,

A further object resides in the provision of an includes a pair of crankcheeks 22 and 24 united improved'vibration absorbing construction of theby a crankpin 26 and carrying at their ends opcharacter indicated whichutilizes certain eleposite the crankpin counterweights as indicatedments of the power plant for its vibration absorbat 28 and 30. Bearingportions as indicated at ing action to absorb or reduce the vibrational32 and 34 are provided on the outer faces of the effects set up by thepower plant with a mini respective crank cheeks 22 and 24 to rotatablymum of additional parts. support the crankshaft in the en A 0 Otherobjects and advantages will be more pare ing rod or master d 36 soperatively 0- ticularly pointed out hereinafter or will become ciatedwith the crankpin 26 at one end by means 18 apparent, a th descriptionroceeds, of a suitable crank bearing and is operatively In theaccompanying drawings, in which like connected at its opposite end withthe usual enreference numerals are used to designate similar ginepiston. The construction so far described parts throughout, there isillustrated by way of is conventional internal combustion engineconexample, a suitable mechanical embodiment of struction familiar tothose skilled in the art and the invention. The drawings, however, arefor constitutes only an environment for the improved 20 the purpose ofillustration only and are not to be vibration absorber which will now bedescribed.

taken as in any way limiting or restricting the One of the counterweighs, r e p e t scope of the invention as set out in the appended fro tounte e ght is made separate from the cla ms. corresponding crank cheek24 and is pivotally se- In the drawings, cured to the crank cheek bysuitable means such 25 Fig. 1 is an elevational view of a fragmentary asthe pivot pin 38 particularly illustrated :1 Figs. portion of aninternal combustion engine, a por- 2 and 3. As s clearly shown in Fig. 3this pivot. tion thereof being broken away and shown in pin is locatedat a distance from the center lines section to better illustrate theapplication thereto of the crank cheek and counterweight for a purof avibration absorbing arrangement constructed pose which will presentlyappear. A sleeve 4|! 30 according to the invention. surrounds theforward crankshaft main bearing Fig. 2 is an elevational view of thecrankshaft journal .34 and is supported in the engine.main of the engineshown in Fig. 1 showing in vertical bearing 20 and operatively connectedwith the section the application thereto of a vibration abdrive shafti2. This sleeve is provided with a sorbing device constructed accordingto the inradially extending arm 42 adapted to rotate in 5 vention and,the space between the counterweight 30 and the Fig. 3 is an endelevational view of the cranktransverse engine partition 44 whichsupports the shaft and vibration absorbing device illustrated mainbearing 20. At itsv outer end this arm is inFig. 2. v pivotallyconnected to the outer portion of the Referring to e drawings in detail,the nucounterweight so by means of the link 46 which 40 meral Illgenerally indicates a powerplant such is pivotally connected at one endto the outer as an internal combustion engine. A radial type end of thearm 42 by the pivot pin 48 and at its of internal combustion engine suchas is convenouter end to the outer portion of the countertionallyemployed for the propulsion of aircraft weight 30 by the pivot pin 50.The counterweight has been illustrated for the purpose of disclosing mayconveniently be provided with indentations 45 the invention but it is tobe understood that the or cavities as indicated at 52 and 54 for the endinvention is in no way limited to this particular of the crank check 24and for the link 46 respecform of engine and may find practicalapplication tively. in powerplants other than internal combustion Inoperation as the crankshaft I6 is rotated engines. In the arrangementillustrated a' drive centrifugal force tends to hold the .pivotallyshaft 12 projects from the front end or nosepicce mounted counterweight30 in a position in which l4 of the engine and may support and drive aits center of mass is the greatest possible distance propulsive devicesuch as the aeronautical profrom the pivot pin 38. As the pivot pin 38is peller l5 schematically shown on a reduced scale. somewhat ofi centerwith respect to the counter- 55 The engine is provided with a crankshaftgenweight, the centrifugal force acting upon the 55 counterweightwilltend to turn the counterweight so that its center line intersects thecenter line of the crank cheek 24 at an angle. As the sleeve 40 isfreely rotatable with respect to the front 5 bearing portion 34 ofthecrankshaft all of the engine torque is transmitted from thecrankshaft I8 to the drive shaft l2 through the crank check 24, thecounterweight 30, the arm 42 and the sleeve 40. The pivot pin 38 isoffset from the 10 center of the counterweight 30 in the direction ofrotation of the crankshaft so that the torque forces acting between theouter portion of the counterweight and the outer end of the arm 42 tendsto move the counterweight back against the action of centrifugal forceto its normal position in which the center line of the counterweight issubstantially coincident with the center line of the crank cheek 24, oran extension thereof. As the torque force transmitted from thecrankshaft to the drive shaft varies because of the imposition thereonof vibrational effects originating in the engine ID, the counterweightwill rock to a limited extent about the pivot pin 38 to provide alimited freedom of rotational movement between the crankshaft and thesleeve 40 which drives the drive shaft l2. This limited freedom ofrelative rotational movements is resiliently resisted by the centrifugalforce acting upon the counterweight so that the counterweight, inaddition to serving as a primary balance for the crankpin 26 and big endof the connecting rod or master rod 36 also acts .as a centrifugalcushion element to dampen the vibration set up by the engine and opposethe transmission of such vibration from the crankshaft to the driveshaft and the propeller or other propulsive device connected with thedrive shaft. I

Either the entire counterweight 30 or any portion thereof may bepivotally mounted to serve 40 as a vibration absorbing element and, byproperly proportioning the mass of the movable counterweight element andby properly positioning the pivots 38, 48 and 50 the vibration absorbermay be designed to dampen a particularly objection- 45 able vibrationorder to effectively eliminate the selected order of vibrationalfrequency from the .combination of vibrational harmonics set up by theengine.

While a particular mechanical embodiment of 50 the invention has beenillustrated and described for the purpose of disclosing the invention itis to be understood that the invention is not limited to the particulararrangement so illustrated and described but at changes in the size,shape and 55 arrangement, of parts may be resorted to as come within thescope of the sub-joined claims.

Having now described the invention so that others skilled in the art mayclearly understand the same, what is claimed and what it is desired 30to secure by Letters Patent is as follows:

1. In combination with an engine having a crankshaft, a vibrationabsorber comprising,,a crankshaft counterweight, means for pivotallysupporting said counterweight, a torque transmitting element freelyrotatable relative to said crankshaft, and a torque transmittingconnection between said pivotally mounted counterweight and said torquetransmitting element.

2. In combination with an engine having a crankshaft, avibration-absorber comprising, a crankshaft counterweight, means forpivotally supporting said counterweight, a torque transmitting elementfreely rotatable with respect to said crankshaft, a radially extendingarm on said torque transmitting element, and means providing a pivotalconnection between the outer end of said arm and said pivotally mountedcounterweight.

3. In combination with an engine having a crankshaft, a vibrationabsorber comprising, a crankshaft counterweight, a pivotal connectionbetween said counterweight and said crankshaft offset from the centerline of said counterweight in the direction of crankshaft rotation, atorque transmitting element freely rotatable relative to saidcrankshaft, a radially extending arm on said torque transmittingelement, and means providing a pivotal connection between the outer endof said arm and the outer portion of said pivotally vmountedcounterweight.

4. In combination with an engine having a crankshaft, a vibrationabsorber comprising, a crankshaft counterweight, means for pivotallysupporting said counterweight on said crankshaft, a torque transmittingsleeve element supporting one end of said crankshaft and rotatablerelative thereto, a radially extending arm on said sleeve element, andmeans providing a pivotal connection, between the outer end of said armand the outer portion of said pivotally mounted counterweight.

5. In combination with an engine having a plurality of rotating elementsincluding a crankshaft and a separate power shaft, a vibrationsuppressing connection between said shafts comprising at least one pairof radial arms and a centrifugally actuated weight connecting the outerends of said arms, said weight and at least one of said arms alsofunctioning as rotatable elements of said engine.

6. In an internal combustion engine, a crankshaft having a radiallyextending counterweight support, a counterweight pivotally connected onthe crankshaft side of its center of gravity to the end of said support,a power transmitting member coaxial with said crankshaft and having anarm extending radially therefrom, and a pivotal connection between saidarm and said counterweight on the side of said first mentioned pivotalconnection remote from said' crankshaft, whereby said counterweight actsto balance said crankshaft and to simultaneously provide a part ofa-vibration suppressing connection between said crankshaft and saidtorque transmitting member.

ERLE MARTIN.

